I was resigned to spending my last week of vacation in the backyard. Then I got a call from a friend whose husband had suddenly hurt his back and couldn’t go with her on their long-planned trip to Scotland. Would I like to take his place, accommodations included? And oh yes, she was leaving in two days.

I thought it over for about five seconds before saying yes.

I tell you this not to brag (although woo hoo!! I’m going to Scotland!!!!) but to say that if I hadn’t done a few key things beforehand, I wouldn’t be able to take this trip on such short notice. So: Be ready to go, because you just never know. Here are four things you should consider doing right now, while you have the time:

1. Buy a cellphone you can use overseas. It’s nice to be able to keep your regular phone number when you travel so that family and friends can more easily contact you in case of emergency. Since I have an iPhone 4S, my carrier, Verizon, was able to activate my SIM card over the phone, and the agent walked me through the steps I need to turn my data roaming off, thereby avoiding steep fees. Costs are reasonable: $1.29 a minute for phone calls, 50 cents to text and 5 cents to receive a text. Plus, there’s free 24/7 email support. The verdict from this technophobe: Thumbs up.

2. Apply for a credit card that lets you accumulate frequent-flier miles without commiting to one carrier. No way could I have afforded to buy a ticket for this last-minute trip, so I had to use miles. Luckily, I’ve been accumulating them on my Capital One card, usable on any airline — enough to buy a ticket on Delta, which is offering the best deal to Edinburgh right now.

3. Pack a credit card that doesn’t charge foreign transaction fees. Many cards charge as much as 3 percent per purchase when you use them abroad. Capital One and Bank of America are two companies that offer cards with no international fees (no annual fees, either). Bonus: The Bank of America Travel Rewards card has the built-in computer chip that’s required more and more when charging purchases in Europe.

4. Make sure your passport is up to date. And by up to date, I mean make sure you have at least six months left before it expires. Many countries require this, so if you’re six months or less from your expiration date, renew now — not right before you set off on your trip. Passport rules and regs here.

And now, if you’ll excuse me, gotta go look up the difference between a burn and a brae.